


C10H12N20

by fanficworm



Category: Supernatural
Genre: Alternate Universe - High School, Jock Castiel, M/M, Nerd Dean, Punk Sam
Language: English
Status: Completed
Published: 2015-07-03
Updated: 2015-07-03
Packaged: 2018-04-07 11:25:29
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,250
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4261575
Author URL: https://archiveofourown.org/users/fanficworm/pseuds/fanficworm
Summary: <blockquote class="userstuff">
              <p>Inspired by this post [http://hidinginpandorasbox.tumblr.com/post/98065460987/i-want-a-destiel-high-school-au-where-dean-is-a].<br/>"I want a Destiel high school AU where Dean is a chemistry nerd and Castiel is the popular football player. Dean writes “I like Calcium Sulfur” on his chemistry notes constantly (as a private inside joke with himself). However, Castiel is absent one day and asks for Dean’s notes. Dean freaks out, but since Castiel doesn’t say anything to him about it, he thinks he didn’t catch the reference…<br/>And then the next day, Dean takes out his notes and finds Castiel has written a note of his own in return:<br/>Carbon Arsenic likes you, too."<br/>I'm sorry, this was too cute not to try to write! :)</p>
            </blockquote>





	C10H12N20

The class shuffled uncomfortably as Mr Metatron strolled slowly along the rows of desks, handing back test papers. Dean checked his mark immediately, and groaned as he read his score – 49/50. Ignoring the fact that he’d probably come top of the class, Dean scanned his answers to find the missing mark. He facepalmed – he’d written a one instead of a ten for the number of carbon ions in serotonin. Sam would have said it was symbolic that out of all the mistakes he could have made, Dean had messed up on love. 

Dean sneaked a sideways look at the boy next to him to see how he had done. Actually, Dean snuck several looks at him every lesson, because the boy he sat next to was, in Dean’s opinion, the prettiest boy in school. Castiel Novak was head of the school football team and Dean’s long term crush. He had scruffy dark hair, mesmerizing blue eyes and just a hint of stubble. Dean often found himself hypnotized by the way Cas’ biceps rippled under his tanned skin when he moved.

And not only was Cas mind-blowingly attractive, he was could be the most sarcastic little shit Dean had ever met. Dean was trying to watch him out of the corner of his eye when –

‘I may be failing science, I can always become a stripper in Gabriel’s gay bar.’ Cas commented sarcastically, staring at his pitiful grade. Cas’ blue eyes flicked up to Dean’s and the latter realized with a jolt that Cas was expecting him to answer.

‘I’m sure you aren’t doing that badly,’ Dean replied, kicking himself as he spoke.

Cas stared at him, and Dean knew that Cas knew that Dean knew exactly how well Cas’ grades were doing. 

‘I assure you,’ Cas continued, ‘I will be into pornography before the end of the year.’

Dean was suddenly struck with some very distracting mental images and to his horror, felt his cheeks burning. Shit, he thought, could I be any more obvious?

The bell rang, saving Dean from any more embarrassment. 

‘Castiel Novak, please stay behind to see me after class,’ shouted Mr Metatron. Cas stopped getting up and returned to his seat, looking resigned. 

‘See you, Cas,’ Dean said hurriedly as he gathered his books and almost ran out of the classroom, face pink. 

Dean was sitting with Garth and Lisa in the library when Sam turned up. 

‘Dean, I need your help,’ he asked, smiling at the girls.

‘Sure, what’s up?’ Dean answered, curious.

‘Uh…,’ Sam blushed. Dean had a feeling this ran in the family. ‘Could I ask you privately?’

As soon as Dean and Sam got to the far end of the school oval, Dean asked, ‘What did you want to ask me, buddy?’

‘Well,’ Sam began slowly, ‘there’s this girl I like in my class. She’s called Jess and she has long blonde hair. I think she’s friends with Anna Novak.’ 

‘I don’t know a lot about girls,’ Dean laughed. ‘I’ve only dated boys so far.’

‘NO,’ Sam continued, ‘it’s just she’s asked me to tutor her in chemistry and I said yes.’

‘And…?’

‘Dean, I suck at chemistry. I need you to give me a crash course so I don’t look like an idiot when she comes over today.’

Dean sighed. ‘What do you need to know?’

After Dean had explained very quickly the entirety of Sam’s year’s chemistry course, the bell rang for afternoon classes. 

‘Thanks, Dean,’ said Sam gratefully.

‘No problem,’ Dean replied. ‘Hey – are you wearing eyeliner?’

‘Yeah,’ Sam said. ‘All the boys in my favourite bands wear it. Jess thinks it looks cool.’

‘Don’t let Dad see it, ok?’

‘Of course,’ Sam laughed and ran off. 

Dean was watching Sam run away across the oval when he turned suddenly, hearing the sound of heavy breathing behind him. 

Cas Novak was bending over, panting. Dean couldn’t believe he hadn’t heard him jog over. Cas straightened up and mopped his forehead with his shirt, flashing Dean a long glimpse of his toned chest. Dean’s eyes flicked irresistibly over Cas’ abs and bulging pecs, before catching Cas’ eyes and looking away quickly. Cas’ face was flushed and sweaty from jogging, and though his mouth was open as he panted, Dean was sure Cas’ lips twitched into a smile. Dean mumbled an indistinct nothing and made off quickly in the opposite direction before his burning cheeks could give him away.

The next science lesson, Dean arrived at school in a good mood. Sam had burst into his room late at night to inform him that the study date had gone brilliantly. Both he and Jess had known that Sam had no idea about chemistry, and they’d ended up watching a movie together on the couch. Dean had spent the night marathoning TV series with Charlie and crying over their favourite characters. 

However, ten minutes into the lesson, Dean’s good mood had worn off. Every day he eagerly awaited the butterflies that fluttered in his stomach as he sat next to Cas in science, the thrill of being close to him and covertly watching his mannerisms. Today, though, Cas did not arrive, and Dean was left feeling strangely cheated as he looked at the empty seat beside him. He doodled, ‘I like calcium sulfur,’ on his notes for the hundredth time – it was a kind of inside joke with himself. 'I like CaS.'

The following lesson, Cas arrived at school looking tired and grumpy. His sarcastic comments were more cutting than usual and he paid no attention to Dean. He breathed out of his mouth and sniffed loudly every five seconds. At the end of the lesson, though, Cas caught Dean before Dean could escape and asked him in a very thick voice if he could borrow yesterday’s notes. 

‘Sure,’ Dean smiled, stuffing the notes into Cas’ hands. ‘See you!’ he shouted, fleeing the classroom. 

As Dean unlocked his locker, he froze. He remembered the millions of ‘I like calcium sulfur’s scrawled throughout his notes. As soon as he got on the bus, he raced to claim the seat next to Charlie, bumping past Dorothy and receiving angry looks from both girls. 

‘Charlie!’ he whispered urgently. Charlie’s expression changed as she realized how upset he was. ‘I handed Cas my science notes and they have the words ‘I like calcium sulfur’ written all over them!’

Charlie looked as if she wanted to laugh, but stayed serious. 

‘It’s cool – the guy’s awful at chem. I bet you he’ll just think you’re really passionate about covalent bonding or something. Relax.’

Charlie’s soothing words had some effect on Dean, and when his stop came, she obviously felt he was recovered enough for her to shove him out of her seat playfully. ‘Get out now. I’ve got business with a couple of very attractive girls and I’m not keen on postponing it.’

Dean only half listened to Sam’s stories about how he and Jess were a couple now. He was imagining Cas laughing as he deciphered Dean’s writing in the margins. It’s okay, he thought, Cas sucks at chemistry.

The next day, when Cas handed Dean’s notes back, he smiled at him for a little longer than usual. Dean urgently flipped through his notes, checking to see if everything was in order. What he didn’t expect, however, was the way his heart caught in his throat as he read the untidy handwriting in the latest page of his notes – ‘Carbon Arsenic likes you too <3’.

**Author's Note:**

> Thank you for reading! This is my first fic on AO3. :)  
> Please leave kudos or comment if you like my work, it means a lot and also that there will be more coming!


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